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Friday, 3 April 2015

Erupting volcanoes - Nishinoshima, Villarica, Cascades Range

03/04/2015. - Nishinoshima, Japon :

NishinoshimaIslandvolcanocontinues itsactivity,lava flowsincreaseits size with also volcanic ashemissions.A reconnaissance flightcarried25 March 2015found that theeruptionsare still common, between 5 and 6per minute, while the activity is similar tothat observed in theprevious flightof February 23. However, sinceFebruary 23, 2015, there hasbeen littleincrease in the sizeof the island.This is becausemost of theflows havechanged direction, andinstead of goingto the west, they nowflow northon the oldestlava.They moveslowly, perhaps because theyslow downbecause of thetopography.Moreover, contraryto February,the volumeof volcanic ashemitted into theatmosphere has increasedsuggesting thatthe starting pointof the eruptions is deeper.

size:East-West: 2000meters.(February 23: 1950 m).NordSouth: 1 800 meters, unchanged.The newareais 2.45km2, an increase of0.16km2since25 December2014.The total sizeof the island is2.46km2, includingpart of the landthat is stillnot covered by thelava.First approach tothe islandby boat from thestart of the eruption:Anavy shipmade anapproach tothe islandfor the first timesince November2013.The scientists,mainly from theJapan Agency forMarineScience andTechnology, said theywere watchingsmallearthquakesand tsunamisassociated withmicroseismic activityof the seabedandlandslidesfrom thevolcanic soilnear the island. They could beinstalled sixmeasuring equipmenton the seabednear the islandto monitorearthquakesand tsunamis.The form ofthe shock wavewas recordedfromthe data associated witha video madefrom theboats and abathymetric surveywas conductedat 6 km,notobservingany activityor changesfrom 2008.The teamalso plans toestablish a systemto monitor conditionsin real time onthe island.Source : AVCAN. Photos : Garde cote japonaise. Villarica, Chili :Thesystem showsvolcanicactivity similarto that reportedin recent days,recordingseismic signalscontinued, with a slightupward trendand temporalcorrespondence withacoustic signalsassociated withthe appearance of smallStrombolianexplosions inthe behaviorof the crater.Such behavioris part of thesuggestedalerttype forthe moment.The volcanicsystem is in aphase ofincreased volatility, which mayprogress rapidly toan eruptivepulsesimilar to thatoccurredon 3March, with possibly of lavaemission.The alert levelremains atORANGE,according to the protocolwhichmeans "probableeruptionin the short term."Source : Sernageomin . Photo :Puconia.cl.Cascades Range Volcanoes, United States of America :
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREENActivity
Update:
All volcanoes in the Cascade Range of Oregon and Washington are
at normal background levels of seismicity. These include Mount Baker,
Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in
Washington State; and Mount Hood, Mount Jefferson, Three Sisters,
Newberry, and Crater Lake in Oregon. Additionally, GPS data from most
of the major volcanoes, and sparse real-time hydrologic and geochemical
monitoring, show no anomalous activity.Recent Observations:
Mount Rainier experienced a short-lived earthquake
swarm March 23/24, with most events occurring during a ~30-minute burst
on March 23. The Pacific Northwest Seismic Network located twenty of
these events, centered mainly beneath the upper south flank at 2/3 km
depth. Magnitude of the located events ranged from 1.6 down to negative
0.7. Such swarms occur sporadically at Mount Rainier, but this week
was the most substantial, by number of earthquakes, since a ~1000-event
episode September 20/22, 2009. An analysis published in 2013 suggests
that earthquakes of the 2009 swarm were initiated by hydrothermal fluid
movement along cracks or small faults, as is likely the case for the
March 23/24 swarm. Source : CVO. Photo :Walter Siegmund